It is sometimes desirable to ensure that two electrical appliances are plugged into the same domestic electrical network, in particular when one wishes to ensure that they are located in the same residence.
For example, when a service provider—for example a provider of video content—offers a second subscription at reduced price on condition that the same residence already benefits from a first subscription, one wishes to be able to verify that the two electrical appliances (each benefiting from one of the subscriptions) are actually at the same residence, that is to say on the same domestic electrical network.
It has long been known how to benefit from the fact that electrical appliances share the same electrical network in order to facilitate their interaction, as described, for example, in U.S. Pat. No. 3,882,392.
It is known, in particular, to make the electrical appliances of one and the same domestic electrical network hold a dialogue with one another by virtue of the technology of carrier currents, as is described in Patent Application WO 98/18211.
The possibility of making two appliances communicate by carrier currents does not however make it possible to ensure that the two appliances are in the same residence. Specifically, when the two domestic networks are not separated by a transformer, communication from one network to the other is possible if no particular provision for isolation is made (reference may be made in this regard to Patent Application WO 2001/54297).